Pneumatic subsurface pumps are well known. Typically, they are used to remove fluids from a hole, or a well. In this manner, the pump is placed in a well with separate lines attached to it for liquid discharge, compressed air flow, and venting. A chamber of the pump fills with a liquid when compressed air has been completely exhausted from it. After the pump is full of liquid, compressed air is introduced into the chamber to pressurize it and cause the water to flow through a liquid discharge pipe.
Fluid enters the pump, typically through a liquid inlet port, flowing past an inlet check valve into the chamber. A float is disposed within the chamber to actuate a valve system to change the state of the pump from a pressurized state to an exhaust state. The float moves in relation to the volume of liquid in the chamber.
U.S. Pat. No. 5,141,404 to Newcomer et al. shows a subsurface pump for removing underground fluids from a well that features an elongated body having an inner and outer chamber with a valve controlling the flow of compressed air into the outer chamber in response to the motion of a float. The float is disposed within the outer chamber and slides up and down in accord with the fluid level within that chamber. As the fluid level increases, the float traverses along the length of the elongated body until it contacts a first float stop on a actuator rod. The actuator rod is attached to an actuator head disposed in a magnetic field.
At a preset point, the upward force of the float overcomes the magnetic field and changes the state of the inner chamber from an exhaust state to a pressurized state, by allowing compressed air to ingress into the chamber. The compressed air causes the fluid to exit the pump by flowing the fluid from the outer chamber through the inner chamber. As the fluid decreases in the chamber, the float lowers until it reaches the lower float actuator rod stop. The continuing weight of the float on the stop pulls the rod down and once again causes the pump to change states, i.e., pressurized to exhaust. Similar pneumatic pumps are shown in U.S. Pat. No. 5,004,405 to Breslin and U.S. Pat. No. 4,467,831 to French. A major drawback with the aforementioned pumps is the size of the float necessitated to change the pump from a pressurized to an exhaust state, resulting in a reduced amount of flow for a given size pump.
It is an object, therefore, of the present invention to provide a pump with a substantially increased flow rate by reducing the size of the float contained in the pump chamber.
It is another object of the present invention to provide a pump with a flow metering system.